PSYCH 25 Ch 5: Physical Development

Asian-American/African-American/North Americans/Northern Europeans/Australians Fill in blanks with any one of the ethnicities listed above ______ and ______ children mature relatively earlier than ______, ______, and ______ children. However, on average, folks from ______ and ______ families are smaller in overall stature.

*Asian-American* and *African-American* children mature relatively earlier than *North Americans*, *Northern Europeans* and *Australians*. However, on average, folks from *Asian-American* and *African-American* families are smaller in overall stature.

______ (girls/boys) begin their growth spurt significantly earlier than ______ (girls/boys). ______ (girls/boys) begin their growth spurt at about age ______ , and ______ (girls/boys) begin theirs about ______ years later.

*Girls* begin their growth spurt significantly earlier than *boys*. *Girls* begin their growth spurt at about age *10 ½*, and boys begin theirs about *2 ½* years later.

Greater activity in the frontal systems, which happens towards the end of development, is associated with the capacity to _____, _____, _____, and _____. These are also called the "_____ functions." They are underdeveloped in adolescents! Should adolescents be allowed to drive? Vote? Enlist in the military? Be tried as adults?

*frontal* systems, the capacity to modulate emotions, control impulses, focus, and switch fluidly from one task to the next. also called the "executive functions."

By six months of age, the newborn has gone from displaying the _____ reflex, to the _____ grasp and then soon on to the _____ grasp. This is evidence that the brain is developing normally. Many screening tests for newborn focus on this as the basis for their assessments.

*palmar* reflex, to the *ulnar* grasp and then soon on to the *pincer* grasp

The _____ and the _____ are parts of the brain that allow us to concentrate on a subject for lengthy periods—are not fully myelinated at puberty

*reticular formation* and the *frontal cortex*

at birth, the most highly developed areas are the _____ brain centers - first the ____, which controls:

*subcortical* (lower) brain centers, the *brain stem*, which controls basic physiological functions like breathing, inborn reflexes, consciousness, reflexes, digestion, elimination, etc.

When does the lymphoid system reach its highest capacity?

Adolescence

Babies ______ their birth weight by ____-____ months of age, and ______ it to about ______ lbs. by age ____ . Toddlers at age ____ are approximately ____ of their adult height.

Babies *double* their birth weight by *4 to 6* months of age, and *triple* it to about *21-22* lbs. by age *1*. Toddlers at age *2* are approximately *½* of their adult height.

Babies are born with ______ (more/less) and ______ (softer/harder) bones than older children and adults.

Babies are born with *more* and *softer* bones than older children and adults

Why is it easy for babies to fall over?

Because babies are "top heavy" (the head is proportionately large at birth, and the trunk and limbs are short)

Children grow in spurts, gaining as much as ______ in a single day!

Children grow in spurts, gaining as much as *1 centimeter* in a single day!

During the first year of life, the ______ (trunk/hands and feet) grow(s) faster than the ______ (trunk/hands and feet) but by puberty, the ______ (trunk/hands and feet) grow(s) faster than the ______ (trunk/hands and feet)

During the first year of life, the *trunk* grows faster than the *hands and feet*, but by puberty, the *hands and feet* grow faster than the *trunk*

T/F: Babies who walk early are inclined to be especially bright

F

T/F: a person's hormones have little effect on human growth and development until puberty

F

T/F: the process of myelinization is finished by the end of early childhood

False. Although myelinization proceeds very rapidly over the first few years of life, some areas of the brain are not completely myelinated until the mid- to late teens or early adulthood

T/F: all parts of the brain develop at the same rate

False. Not all parts of the brain develop at the same rate.

T/F: each hemisphere of the brain is totally independent of the other

False. The corpus callosum, which connects the hemispheres, plays an important role in integrating their respective functions

why is the corpus callous useful?

It connects the right and left hemispheres of the brain, and the left side of the controls the right side of the body, and the right side of the brain controls the left side of the body (called the contralateral side).

Neurons can be ______ or ______

Neurons can be *excitatory* or *inhibitory*

Once they start developing, ______ (girls/boys) start to grow faster than ______ (girls/boys).

Once they start developing, *girls* start to grow faster than *boys*.

Bones ______ (or get harder) as kids get older

Ossify

T/F: 2. The average 2-year-old is already about half of his or her adult height

T

T/F: Growth is very uneven in infancy

T

T/F: Half the nerve cells in the average baby's brain die over the first few years of life

T

T/F: Individual neurons have the potential to serve any neural function, and the function each serves depends on where it ends up

T

T/F: Most children walk when they are ready, and no amount of encouragement will enable a 6-month-old to walk alone

T

T/F: The newborn's head is already 70 percent of its eventual adult size and represents one quarter of total body length, the same fraction as the legs

T

T/F: Throughout infancy and childhood, the body grows in a proximodistal direction, but this center-outward growth pattern reverses just before puberty

T

T/F: despite their very different early experiences, infants from around the world progress through roughly the same sequence of motor milestones

T

T/F: emotional trauma can seriously impair the physical growth of young children, even those who are adequately nourished, free from illness, and not physically abused

T

T/F: the formation of new neurons in the hippocampus occurs throughout life

T

David Walsh: "Why They Act The Way They Do"

Teens are impulsive and have moodiness, quickness to show anger and take risks because they can't make use of their prefrontal cortex and rely on their amygdala Ted talk

within the cerebrum and cerebral cortex, which areas develop first, and which areas develop later?

The *primary motor areas* (which control simple motor activities such as waving the arms) develop first, and then the *primary sensory areas* (which control sensory processes such as vision, hearing, smelling, and tasting). This development is evident in the waning of inborn reflexes into the capacity for more sophisticated, voluntary movement

What may be a reason that the attention spans of infants, toddlers, and school-age children are much shorter than those of adolescents and adults?

The *reticular formation* and the *frontal cortex* are not fully myelinated at puberty

The _____ areas of the brain develop first, and the _____ and _____ develop later.

The *subcortical* areas of the brain develop first (brain stem, involved with basic physiological functions like breathing, consciousness, reflexes, digestion, etc), and the *cerebrum* and *cerebral cortex* develop later

What brain functions are the last to develop? What are they associated with? How late (at least) are they still developing

The higher cortical functions. They're associated with higher order, more abstract thinking. They are still developing through the late teens at least

What are the characteristics of the neonate's skull that make it easier for the neonate to pass through the birth canal?

The neonate's skull is comprised of several soft bones that can be compressed without brain damage during the birthing process

The skull bones are joined together over time, fusing together around ___ soft areas called ______. The areas where they fuse are called ______.

The skull bones are joined together over time, fusing together around *6* soft areas called *fontanelles*. The areas where they fuse are called *sutures*

What grows the fastest during the first year of life?

The trunk

What is there some evidence of regarding left-handedness and cerebral laterization?

There is some evidence that cerebral lateralization may be reversed in some people who are left handed.

T/F: The lymphoid system is larger in adolescents than it is in full grown adults

True

T/F: There's a huge amount of variation in the timing of development between different ethnicities/races

True

T/F: synaptic pruning occurs during adolescence

True

T/F: the cerebrum includes the corpus callosum

True

What event during development improves an infant or child's ability to process and respond to socially important emotional input (e.g. the expressions of fear or disapproval on a parent's face), and their ability to monitor their own emotional reactions?

When myelinization enhances the efficiency between the more primitive, emotive subcortical areas of the brain and the more regulatory prefrontal cortical areas of the brain

*skeletal age*

a measure of physical maturation based on the child's level of skeletal development This method of estimating a child's level of physical maturation uses an X-ray his or her wrist and hand. The X-ray shows the number of bones and the extent of their ossification, which is then interpretable as a skeletal age

guiding cells

a network of cells in a developing embryo that lay pathways which allow newly developed neurons to migrate from the neural tube to form the major parts of the brain

*proximodistal development*

a sequence of physical maturation and growth that proceeds from the center of the body (the proximal region) to the extremities (distal regions)

*cephalocaudal development*

a sequence of physical maturation and growth that proceeds from the head (cephalic region) to the tail (or caudal region)

dynamical systems theory

a theory that views motor skills as active reorganizations of previously mastered capabilities that are undertaken to find more effective ways of exploring the environment or satisfying other objectives. Infants hope to acquire and perfect new motor skills that will help them to get to interesting objects they hope to explore or to accomplish other goals they may have in mind. Motor skills actually represent an active and intricate reorganization of several existing capabilities that is undertaken by a curious, active infant who has a particular goal in mind

Newborns are born with ____ of the muscle fibers they will have at adulthood

all

Why do C-section babies often look better right after birth than vaginally-delivered babies

because their skulls don't need to compress to complete the birthing process

the *motor cortex* controls:

body movements

the *sensory cortex* controls:

body sensations

*plasticity*

capacity for change; a developmental state that has the potential to be shaped by experience.

each of the hemispheres of the brain are covered by the _____, an outer layer of gray matter that controls sensory and motor processes, perception, and intellectual functioning.

cerebral cortex

What the areas in the brain most directly implicated in voluntary bodily movements, perception, and higher intellectual activities such as learning, thinking, and language.

cerebrum and cerebral cortex

The _____ and _____ develop in the the brain later, after the _____ has already developed. Of these two areas, the _____ areas develop first, followed by the _____ areas. How is this development evident in babies?

cerebrum, cerebral cortex. primary motor areas, primary sensory areas. This development is evident in the waning of inborn reflexes into the capacity for more sophisticated, voluntary movement.

primary sensory areas

control sensory processes such as vision, hearing, smelling, and tasting

primary motor areas

control simple motor activities, such as waving the arms

right cerebral hemisphere

controls the left side of the body and contains centers for processing visual-spatial information, nonlinguistic sounds such as music, tactile (touch) sensations, and expressing negative emotions

maturational viewpoint

describes motor development as the unfolding of a genetically programmed sequence of events in which the nerves and muscles mature in a downward and outward direction

the left and right cerebral hemispheres serve _____ (same/different) functions and control ____ (same/different) areas of the body

different, and different

When is handedness determined? Earlier or later in development?

earlier.

This process of synaptogenesis is affected by

environmental stimulation (monkey and cat studies).

the *cerebellum* controls:

equilibrium and coordination

*synaptogenesis*

formation of connections (synapses) among and between neurons. proceeds rapidly during the brain growth spurt This process if effected by environmental stimulation (monkey and cat studies). 1

Who begins the growth spurt earlier: girls or boys?

girls

What are the higher cortical functions associated with?

higher order, more abstract thinking

prefrontal cortex* (finish this definition)

involved in such higher-level cognitive activities as strategic planning

What functions are specialized in the left cerebral hemisphere?

language and verbal skills

the left cerebral hemisphere controls the _____ side of the body, and the right cerebral hemisphere controls the _____ side of the body

left hemisphere controls the right side of the body, right cerebral hemisphere controls the left side of the body

at birth, the most highly developed areas are the _____

lower (subcortical) brain centers, which control states of consciousness, inborn reflexes, and vital biological functions such as digestion, respiration, and elimination.

Greater activity in the frontal systems is also associated with the capacity to _____, _____, and _____. (these are also called the "_____ functions")

modulate emotions, control impulses, focus, and switch fluidly from one task to the next. executive functions.

the ankles, wrists, feet, and hands develop ______(more/fewer) bones as the child matures

more

*glia*

nerve cells that nourish neurons and encase them in a sheath that insulates them and promotes rapid transmission of neural impulses. This is the process of myelination. Myelination occurs for about 2 ½ years after birth. The nervous system is especially plastic during this developmental period.

*neurons*

nerve cells that receive and transmit neural impulses. the basic unit of the brain and nervous system

Why are human neonates reflexive, "sensory-motor" beings?

only the sensory and motor areas of the cortex are functioning well at birth. By 6 months, the primary motor areas of the cerebral cortex have developed enough that they now direct most of the infant's movements. Inborn responses such as the palmar grasp and the Babinski reflex should have disappeared by now, thus indicating that the higher cortical centers are assuming proper control over the more primitive subcortical areas of the brain

The Experiential (or Practice) Hypothesis

opportunities to practice motor skills are important for development. maturation is necessary but not sufficient for the development of motor skills.

the *parietal lobe* controls:

perception

cerebral laterization

refers to the specialization of functions in the left and right cerebral hemispheres (left=language, verbal skills; right= visuospatial reasoning) also involves a preference for using one hand or one side of the body more than the other

*fontanelles*

six soft spots that separate the skull bones in infants, that are gradually filled in by minerals to form a single skull by age 2

what phenomenon in brain development is likened to developing information "superhighways"?

synaptic pruning

What are the first areas of the cerebrum to mature?

the *primary motor areas* (which control simple motor activities such as waving the arms) and the *primary sensory areas* (which control sensory processes such as vision, hearing, smelling, and tasting)

corpus callosum

the bundle of neural fibers that connects the two hemispheres of the brain and transmits information from one hemisphere to the other. Plays an important role in integrating the left and right hemispheres' respective functions

*synapse* or *synaptic cleft*

the connective space (juncture) between one nerve cell (neuron) and another

left cerebral hemisphere

the hemisphere of the brain that controls the right side of the body, and contains centers for speech, hearing, verbal memory, decision making, language processing, and expression of positive emotions

*cerebrum*

the highest (most evolved) brain center; includes both hemispheres of the brain and the fibers that connect them (the corpus callosum)

How do we explain the sequencing and timing of early motor development?

the maturational viewpoint, the experiential (or practice) hypothesis, and the dynamical systems theory

*cerebral cortex*

the outer layer of the brain's cerebrum that is made up of gray matter and is involved in voluntary body movements, sensory and motor processes, perception, and higher intellectual functions such as learning, thinking, and speaking

*brain growth spurt*

the period between the 7th prenatal month and 2 years of age when more than half of the child's eventual brain weight is gained.

*myelinization*

the process by *glia* cells encase neurons in waxy myelin sheaths that will insulate them and promote rapid transmission of neural impulses, allowing the brain to communicate more efficiently with different parts of the body. this occurs for about 2 ½ years after birth. The nervous system is especially plastic during this developmental period.

synaptic pruning

the process by which neurons that are stimulated infrequently in a highly plastic brain lose their synapses

*sutures*

the seams where the skull bones join, that allow the skull to expand as the brain grows larger

What are the only areas of the cortex that are functioning well at birth?

the sensory and motor areas of the cortex

the *spinal cord* controls:

transmission of neural impulses to and from the brain

*Wernicke's area* controls _____ and is located in the _____(left/right/both) hemisphere(s) of the brain

understanding of spoken language, left

the *occipital lobe* controls:

vision

What functions are specialized in the right cerebral hemisphere?

visuospatial reasoning

does myelinization follow a chronological sequence that is consistent with the maturation of the rest of the nervous system.?

yes. at birth or shortly after, the pathways between the sense organs and brain are reasonably well myelinated (and the neonate's sensory equipment is in good working order). as neural pathways between the brain and the skeletal muscles myelinate (in a cephalocaudal and proximodistal pattern), the child becomes capable of increasingly complex motor activities